[disorder] / lib / uaudio-alsa.c

/*
 * This file is part of DisOrder.
 * Copyright (C) 2009 Richard Kettlewell
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
/** @file lib/uaudio-alsa.c
 * @brief Support for ALSA backend */
#include "common.h"

#if HAVE_ALSA_ASOUNDLIB_H

#include <alsa/asoundlib.h>

#include "mem.h"
#include "log.h"
#include "uaudio.h"

/** @brief The current PCM handle */
static snd_pcm_t *alsa_pcm;

static const char *const alsa_options[] = {
  "device",
  "mixer-control",
  "mixer-channel",
  NULL
};

/** @brief Mixer handle */
snd_mixer_t *alsa_mixer_handle;

/** @brief Mixer control */
static snd_mixer_elem_t *alsa_mixer_elem;

/** @brief Left channel */
static snd_mixer_selem_channel_id_t alsa_mixer_left;

/** @brief Right channel */
static snd_mixer_selem_channel_id_t alsa_mixer_right;

/** @brief Minimum level */
static long alsa_mixer_min;

/** @brief Maximum level */
static long alsa_mixer_max;

/** @brief Actually play sound via ALSA */
static size_t alsa_play(void *buffer, size_t samples) {
  int err;
  /* ALSA wants 'frames', where frame = several concurrently played samples */
  const snd_pcm_uframes_t frames = samples / uaudio_channels;

  snd_pcm_sframes_t rc = snd_pcm_writei(alsa_pcm, buffer, frames);
  if(rc < 0) {
    switch(rc) {
    case -EPIPE:
      if((err = snd_pcm_prepare(alsa_pcm)))
	fatal(0, "error calling snd_pcm_prepare: %d", err);
      return 0;
    case -EAGAIN:
      return 0;
    default:
      fatal(0, "error calling snd_pcm_writei: %d", (int)rc);
    }
  }
  return rc * uaudio_channels;
}

/** @brief Open the ALSA sound device */
static void alsa_open(void) {
  const char *device = uaudio_get("device", "default");
  int err;

  if((err = snd_pcm_open(&alsa_pcm,
			 device,
			 SND_PCM_STREAM_PLAYBACK,
			 0)))
    fatal(0, "error from snd_pcm_open: %d", err);
  snd_pcm_hw_params_t *hwparams;
  snd_pcm_hw_params_alloca(&hwparams);
  if((err = snd_pcm_hw_params_any(alsa_pcm, hwparams)) < 0)
    fatal(0, "error from snd_pcm_hw_params_any: %d", err);
  if((err = snd_pcm_hw_params_set_access(alsa_pcm, hwparams,
                                         SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
    fatal(0, "error from snd_pcm_hw_params_set_access: %d", err);
  int sample_format;
  if(uaudio_bits == 16)
    sample_format = uaudio_signed ? SND_PCM_FORMAT_S16 : SND_PCM_FORMAT_U16;
  else
    sample_format = uaudio_signed ? SND_PCM_FORMAT_S8 : SND_PCM_FORMAT_U8;
  if((err = snd_pcm_hw_params_set_format(alsa_pcm, hwparams,
                                         sample_format)) < 0)
    fatal(0, "error from snd_pcm_hw_params_set_format (%d): %d",
          sample_format, err);
  unsigned rate = uaudio_rate;
  if((err = snd_pcm_hw_params_set_rate_near(alsa_pcm, hwparams, &rate, 0)) < 0)
    fatal(0, "error from snd_pcm_hw_params_set_rate_near (%d): %d",
          rate, err);
  if((err = snd_pcm_hw_params_set_channels(alsa_pcm, hwparams,
                                           uaudio_channels)) < 0)
    fatal(0, "error from snd_pcm_hw_params_set_channels (%d): %d",
          uaudio_channels, err);
  if((err = snd_pcm_hw_params(alsa_pcm, hwparams)) < 0)
    fatal(0, "error calling snd_pcm_hw_params: %d", err);
  
}

static void alsa_activate(void) {
  uaudio_thread_activate();
}

static void alsa_deactivate(void) {
  uaudio_thread_deactivate();
}
  
static void alsa_start(uaudio_callback *callback,
                      void *userdata) {
  if(uaudio_channels != 1 && uaudio_channels != 2)
    fatal(0, "asked for %d channels but only support 1 or 2",
          uaudio_channels); 
  if(uaudio_bits != 8 && uaudio_bits != 16)
    fatal(0, "asked for %d bits/channel but only support 8 or 16",
          uaudio_bits); 
  alsa_open();
  uaudio_thread_start(callback, userdata, alsa_play,
                      32 / uaudio_sample_size,
                      4096 / uaudio_sample_size);
}

static void alsa_stop(void) {
  uaudio_thread_stop();
  snd_pcm_close(alsa_pcm);
  alsa_pcm = 0;
}

/** @brief Convert a level to a percentage */
static int to_percent(long n) {
  return (n - alsa_mixer_min) * 100 / (alsa_mixer_max - alsa_mixer_min);
}

/** @brief Convert a percentage to a level */
static int from_percent(int n) {
  return alsa_mixer_min + n * (alsa_mixer_max - alsa_mixer_min) / 100;
}

static void alsa_open_mixer(void) {
  int err;
  snd_mixer_selem_id_t *id;
  const char *device = uaudio_get("device", "default");
  const char *mixer = uaudio_get("mixer-control", "0");
  const char *channel = uaudio_get("mixer-channel", "PCM");

  snd_mixer_selem_id_alloca(&id);
  if((err = snd_mixer_open(&alsa_mixer_handle, 0)))
    fatal(0, "snd_mixer_open: %s", snd_strerror(err));
  if((err = snd_mixer_attach(alsa_mixer_handle, device)))
    fatal(0, "snd_mixer_attach %s: %s", device, snd_strerror(err));
  if((err = snd_mixer_selem_register(alsa_mixer_handle,
                                     0/*options*/, 0/*classp*/)))
    fatal(0, "snd_mixer_selem_register %s: %s",
          device, snd_strerror(err));
  if((err = snd_mixer_load(alsa_mixer_handle)))
    fatal(0, "snd_mixer_load %s: %s", device, snd_strerror(err));
  snd_mixer_selem_id_set_name(id, channel);
  snd_mixer_selem_id_set_index(id, atoi(mixer));
  if(!(alsa_mixer_elem = snd_mixer_find_selem(alsa_mixer_handle, id)))
    fatal(0, "device '%s' mixer control '%s,%s' does not exist",
	  device, channel, mixer);
  if(!snd_mixer_selem_has_playback_volume(alsa_mixer_elem))
    fatal(0, "device '%s' mixer control '%s,%s' has no playback volume",
	  device, channel, mixer);
  if(snd_mixer_selem_is_playback_mono(alsa_mixer_elem)) {
    alsa_mixer_left = alsa_mixer_right = SND_MIXER_SCHN_MONO;
  } else {
    alsa_mixer_left = SND_MIXER_SCHN_FRONT_LEFT;
    alsa_mixer_right = SND_MIXER_SCHN_FRONT_RIGHT;
  }
  if(!snd_mixer_selem_has_playback_channel(alsa_mixer_elem,
                                           alsa_mixer_left)
     || !snd_mixer_selem_has_playback_channel(alsa_mixer_elem,
                                              alsa_mixer_right))
    fatal(0, "device '%s' mixer control '%s,%s' lacks required playback channels",
	  device, channel, mixer);
  snd_mixer_selem_get_playback_volume_range(alsa_mixer_elem,
                                            &alsa_mixer_min, &alsa_mixer_max);

}

static void alsa_close_mixer(void) {
  /* TODO alsa_mixer_elem */
  if(alsa_mixer_handle)
    snd_mixer_close(alsa_mixer_handle);
}

static void alsa_get_volume(int *left, int *right) {
  long l, r;
  int err;
  
  if((err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
                                                alsa_mixer_left, &l))
     || (err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
                                                   alsa_mixer_right, &r)))
    fatal(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err));
  *left = to_percent(l);
  *right = to_percent(r);
}

static void alsa_set_volume(int *left, int *right) {
  long l, r;
  int err;
  
  /* Set the volume */
  if(alsa_mixer_left == alsa_mixer_right) {
    /* Mono output - just use the loudest */
    if((err = snd_mixer_selem_set_playback_volume
	(alsa_mixer_elem, alsa_mixer_left,
	 from_percent(*left > *right ? *left : *right))))
      fatal(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err));
  } else {
    /* Stereo output */
    if((err = snd_mixer_selem_set_playback_volume
	(alsa_mixer_elem, alsa_mixer_left, from_percent(*left)))
       || (err = snd_mixer_selem_set_playback_volume
	   (alsa_mixer_elem, alsa_mixer_right, from_percent(*right))))
      fatal(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err));
  }
  /* Read it back to see what we ended up at */
  if((err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
                                                alsa_mixer_left, &l))
     || (err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
                                                   alsa_mixer_right, &r)))
    fatal(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err));
  *left = to_percent(l);
  *right = to_percent(r);
}

const struct uaudio uaudio_alsa = {
  .name = "alsa",
  .options = alsa_options,
  .start = alsa_start,
  .stop = alsa_stop,
  .activate = alsa_activate,
  .deactivate = alsa_deactivate,
  .open_mixer = alsa_open_mixer,
  .close_mixer = alsa_close_mixer,
  .get_volume = alsa_get_volume,
  .set_volume = alsa_set_volume,
};

#endif

/*
Local Variables:
c-basic-offset:2
comment-column:40
fill-column:79
indent-tabs-mode:nil
End:
*/
Commit	Line	Data
4fd38868 RK	1	/*
	2	* This file is part of DisOrder.
	3	* Copyright (C) 2009 Richard Kettlewell
	4	*
	5	* This program is free software: you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation, either version 3 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	*/
	18	/** @file lib/uaudio-alsa.c
	19	* @brief Support for ALSA backend */
	20	#include "common.h"
	21
	22	#if HAVE_ALSA_ASOUNDLIB_H
	23
	24	#include <alsa/asoundlib.h>
	25
	26	#include "mem.h"
	27	#include "log.h"
	28	#include "uaudio.h"
	29
	30	/** @brief The current PCM handle */
	31	static snd_pcm_t *alsa_pcm;
	32
	33	static const char *const alsa_options[] = {
	34	"device",
b50cfb8a RK	35	"mixer-control",
b50cfb8a RK	36	"mixer-channel",
4fd38868 RK	37	NULL
	38	};
	39
b50cfb8a RK	40	/** @brief Mixer handle */
	41	snd_mixer_t *alsa_mixer_handle;
	42
	43	/** @brief Mixer control */
	44	static snd_mixer_elem_t *alsa_mixer_elem;
	45
	46	/** @brief Left channel */
	47	static snd_mixer_selem_channel_id_t alsa_mixer_left;
	48
	49	/** @brief Right channel */
	50	static snd_mixer_selem_channel_id_t alsa_mixer_right;
	51
	52	/** @brief Minimum level */
	53	static long alsa_mixer_min;
	54
	55	/** @brief Maximum level */
	56	static long alsa_mixer_max;
	57
4fd38868 RK	58	/** @brief Actually play sound via ALSA */
	59	static size_t alsa_play(void *buffer, size_t samples) {
	60	int err;
	61	/* ALSA wants 'frames', where frame = several concurrently played samples */
	62	const snd_pcm_uframes_t frames = samples / uaudio_channels;
	63
	64	snd_pcm_sframes_t rc = snd_pcm_writei(alsa_pcm, buffer, frames);
	65	if(rc < 0) {
	66	switch(rc) {
	67	case -EPIPE:
	68	if((err = snd_pcm_prepare(alsa_pcm)))
	69	fatal(0, "error calling snd_pcm_prepare: %d", err);
	70	return 0;
	71	case -EAGAIN:
	72	return 0;
	73	default:
	74	fatal(0, "error calling snd_pcm_writei: %d", (int)rc);
	75	}
	76	}
	77	return rc * uaudio_channels;
	78	}
	79
	80	/** @brief Open the ALSA sound device */
	81	static void alsa_open(void) {
b50cfb8a	82	const char *device = uaudio_get("device", "default");
4fd38868 RK	83	int err;
4fd38868 RK	84
4fd38868 RK	85	if((err = snd_pcm_open(&alsa_pcm,
	86	device,
	87	SND_PCM_STREAM_PLAYBACK,
	88	0)))
	89	fatal(0, "error from snd_pcm_open: %d", err);
	90	snd_pcm_hw_params_t *hwparams;
	91	snd_pcm_hw_params_alloca(&hwparams);
	92	if((err = snd_pcm_hw_params_any(alsa_pcm, hwparams)) < 0)
	93	fatal(0, "error from snd_pcm_hw_params_any: %d", err);
	94	if((err = snd_pcm_hw_params_set_access(alsa_pcm, hwparams,
	95	SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
	96	fatal(0, "error from snd_pcm_hw_params_set_access: %d", err);
	97	int sample_format;
	98	if(uaudio_bits == 16)
	99	sample_format = uaudio_signed ? SND_PCM_FORMAT_S16 : SND_PCM_FORMAT_U16;
	100	else
	101	sample_format = uaudio_signed ? SND_PCM_FORMAT_S8 : SND_PCM_FORMAT_U8;
	102	if((err = snd_pcm_hw_params_set_format(alsa_pcm, hwparams,
	103	sample_format)) < 0)
	104	fatal(0, "error from snd_pcm_hw_params_set_format (%d): %d",
	105	sample_format, err);
	106	unsigned rate = uaudio_rate;
	107	if((err = snd_pcm_hw_params_set_rate_near(alsa_pcm, hwparams, &rate, 0)) < 0)
	108	fatal(0, "error from snd_pcm_hw_params_set_rate_near (%d): %d",
	109	rate, err);
	110	if((err = snd_pcm_hw_params_set_channels(alsa_pcm, hwparams,
	111	uaudio_channels)) < 0)
	112	fatal(0, "error from snd_pcm_hw_params_set_channels (%d): %d",
	113	uaudio_channels, err);
	114	if((err = snd_pcm_hw_params(alsa_pcm, hwparams)) < 0)
	115	fatal(0, "error calling snd_pcm_hw_params: %d", err);
	116
	117	}
	118
	119	static void alsa_activate(void) {
	120	uaudio_thread_activate();
	121	}
	122
	123	static void alsa_deactivate(void) {
	124	uaudio_thread_deactivate();
	125	}
	126
	127	static void alsa_start(uaudio_callback *callback,
	128	void *userdata) {
	129	if(uaudio_channels != 1 && uaudio_channels != 2)
	130	fatal(0, "asked for %d channels but only support 1 or 2",
	131	uaudio_channels);
	132	if(uaudio_bits != 8 && uaudio_bits != 16)
	133	fatal(0, "asked for %d bits/channel but only support 8 or 16",
	134	uaudio_bits);
	135	alsa_open();
	136	uaudio_thread_start(callback, userdata, alsa_play,
	137	32 / uaudio_sample_size,
	138	4096 / uaudio_sample_size);
	139	}
	140
	141	static void alsa_stop(void) {
	142	uaudio_thread_stop();
	143	snd_pcm_close(alsa_pcm);
	144	alsa_pcm = 0;
	145	}
	146
b50cfb8a RK	147	/** @brief Convert a level to a percentage */
	148	static int to_percent(long n) {
	149	return (n - alsa_mixer_min) * 100 / (alsa_mixer_max - alsa_mixer_min);
	150	}
	151
42f738c2 RK	152	/** @brief Convert a percentage to a level */
	153	static int from_percent(int n) {
	154	return alsa_mixer_min + n * (alsa_mixer_max - alsa_mixer_min) / 100;
	155	}
	156
b50cfb8a RK	157	static void alsa_open_mixer(void) {
	158	int err;
	159	snd_mixer_selem_id_t *id;
	160	const char *device = uaudio_get("device", "default");
	161	const char *mixer = uaudio_get("mixer-control", "0");
	162	const char *channel = uaudio_get("mixer-channel", "PCM");
	163
	164	snd_mixer_selem_id_alloca(&id);
	165	if((err = snd_mixer_open(&alsa_mixer_handle, 0)))
	166	fatal(0, "snd_mixer_open: %s", snd_strerror(err));
42f738c2 RK	167	if((err = snd_mixer_attach(alsa_mixer_handle, device)))
42f738c2 RK	168	fatal(0, "snd_mixer_attach %s: %s", device, snd_strerror(err));
b50cfb8a RK	169	if((err = snd_mixer_selem_register(alsa_mixer_handle,
	170	0/options/, 0/classp/)))
	171	fatal(0, "snd_mixer_selem_register %s: %s",
	172	device, snd_strerror(err));
	173	if((err = snd_mixer_load(alsa_mixer_handle)))
	174	fatal(0, "snd_mixer_load %s: %s", device, snd_strerror(err));
	175	snd_mixer_selem_id_set_name(id, channel);
	176	snd_mixer_selem_id_set_index(id, atoi(mixer));
	177	if(!(alsa_mixer_elem = snd_mixer_find_selem(alsa_mixer_handle, id)))
	178	fatal(0, "device '%s' mixer control '%s,%s' does not exist",
	179	device, channel, mixer);
	180	if(!snd_mixer_selem_has_playback_volume(alsa_mixer_elem))
	181	fatal(0, "device '%s' mixer control '%s,%s' has no playback volume",
	182	device, channel, mixer);
	183	if(snd_mixer_selem_is_playback_mono(alsa_mixer_elem)) {
	184	alsa_mixer_left = alsa_mixer_right = SND_MIXER_SCHN_MONO;
	185	} else {
	186	alsa_mixer_left = SND_MIXER_SCHN_FRONT_LEFT;
	187	alsa_mixer_right = SND_MIXER_SCHN_FRONT_RIGHT;
	188	}
	189	if(!snd_mixer_selem_has_playback_channel(alsa_mixer_elem,
	190	alsa_mixer_left)
	191	\|\| !snd_mixer_selem_has_playback_channel(alsa_mixer_elem,
	192	alsa_mixer_right))
	193	fatal(0, "device '%s' mixer control '%s,%s' lacks required playback channels",
	194	device, channel, mixer);
	195	snd_mixer_selem_get_playback_volume_range(alsa_mixer_elem,
	196	&alsa_mixer_min, &alsa_mixer_max);
	197
	198	}
	199
	200	static void alsa_close_mixer(void) {
	201	/* TODO alsa_mixer_elem */
	202	if(alsa_mixer_handle)
	203	snd_mixer_close(alsa_mixer_handle);
	204	}
	205
	206	static void alsa_get_volume(int left, int right) {
	207	long l, r;
	208	int err;
	209
	210	if((err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
	211	alsa_mixer_left, &l))
	212	\|\| (err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
	213	alsa_mixer_right, &r)))
	214	fatal(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err));
	215	*left = to_percent(l);
	216	*right = to_percent(r);
	217	}
	218
	219	static void alsa_set_volume(int left, int right) {
	220	long l, r;
	221	int err;
	222
	223	/* Set the volume */
	224	if(alsa_mixer_left == alsa_mixer_right) {
	225	/* Mono output - just use the loudest */
	226	if((err = snd_mixer_selem_set_playback_volume
	227	(alsa_mixer_elem, alsa_mixer_left,
	228	from_percent(left > right ? left : right))))
	229	fatal(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err));
	230	} else {
	231	/* Stereo output */
	232	if((err = snd_mixer_selem_set_playback_volume
233	(alsa_mixer_elem, alsa_mixer_left, from_percent(*left)))
234	\|\| (err = snd_mixer_selem_set_playback_volume
235	(alsa_mixer_elem, alsa_mixer_right, from_percent(*right))))
236	fatal(0, "snd_mixer_selem_set_playback_volume: %s", snd_strerror(err));
237	}
238	/* Read it back to see what we ended up at */
239	if((err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
240	alsa_mixer_left, &l))
241	\|\| (err = snd_mixer_selem_get_playback_volume(alsa_mixer_elem,
242	alsa_mixer_right, &r)))
243	fatal(0, "snd_mixer_selem_get_playback_volume: %s", snd_strerror(err));
244	*left = to_percent(l);
245	*right = to_percent(r);
246	}
247
4fd38868 RK	248	const struct uaudio uaudio_alsa = {
	249	.name = "alsa",
	250	.options = alsa_options,
	251	.start = alsa_start,
	252	.stop = alsa_stop,
	253	.activate = alsa_activate,
b50cfb8a RK	254	.deactivate = alsa_deactivate,
	255	.open_mixer = alsa_open_mixer,
	256	.close_mixer = alsa_close_mixer,
	257	.get_volume = alsa_get_volume,
	258	.set_volume = alsa_set_volume,
4fd38868 RK	259	};
	260
	261	#endif
	262
	263	/*
	264	Local Variables:
	265	c-basic-offset:2
	266	comment-column:40
	267	fill-column:79
	268	indent-tabs-mode:nil
	269	End:
	270	*/